Rover's results could solve Martian riddle

Scientists already speculating about water's ancient role

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A picture from the Opportunity rover's microscopic imager shows fine layering within Martian bedrock as well as two of the spherical rock grains known as "Martian blueberries." Scientists say such pictures strongly hint at water's role in Mars' ancient past.

LOS ANGELES — Scientists are excitedly speculating that discoveries made by a Mars rover over the weekend will help them finally unravel how much of a role water played in the Red Planet’s geologic history, a science team member said Monday.

Scientists were poring over data and microscopic images returned to Earth by NASA's Opportunity rover, which spent the weekend examining a multilayered rock nicknamed El Capitan embedded in the side of the small crater where Opportunity landed on Jan. 24.

The rover has yet to climb out of the small crater onto the flat Meridiani Planum to examine a large deposit of what may be water-formed hematite.

The science team planned to command the rover to use a rock scraping tool to clear away dust so that its spectrometers can get clearer readings of El Capitan, which lies in an outcrop of bedrock that scientists believe holds the key to the planet’s past.

“There are high expectations that we will understand the extent to which the outcrop has been modified chemically and whether water was involved,” Ray Arvidson, deputy principal investigator, said.

The main purpose of NASA's $820 million twin-rover mission is to determine whether liquid water could have persisted long enough on Mars to support the development of life. Opportunity's landing site has already turned up its share of scientific paydirt, giving scientists their first up-close look at Martian bedrock.

Competing theories
Arvidson said scientists are working on competing theories about how the fine layers in El Capitan's 3-foot-high (meter-high) outcropping were formed, and hoped to have preliminary findings within days.

“One idea is that it’s associated with ash fall or simply windblown material that was compacted,” he said. “Or it’s associated with (sedimentation in) an old lake or shallow sea. The hope is in the end you have the information to show how they were formed and modified.”

Rob Manning, a mission manager for the rovers, agreed that the scientific speculation was on the rise.

"Since I am the mission manager and not representing the science team, I won't comment on their speculations," he told reporters during a teleconference. "But there is a lot of enthusiasm, probably as much enthusiasm as we've ever had by the science team, and a lot of intense discussions over these last several days."

Manning predicted that Opportunity would spend "a fair amount of time" at the outcrop before leaving the area to search for other sites to explore in an area known as Meridiani Planum.

"There's just too much excitement, too much to see," he said.

Further details may emerge Thursday at the next scheduled news briefing.

Spirited away
On the other side of the planet, Opportunity’s twin, Spirit, left the trench that it dug and spent days examining, and rolled toward Bonneville Crater, about 328 feet (100 meters) from its landing site in Gusev Crater — a massive depression the size of Connecticut.

NASA - JPL

A snapshot from the Spirit rover's rear hazard avoidance camera shows tracks leading away from a trench that Spirit dug in the Martian soil several days earlier.

Preliminary data showed that the soil at the sides and bottom of the trench was “coherent,” but scientists were not yet sure what was holding the fine particles together, Arvidson said.

Manning said Spirit spent its 49th Martian day, or sol, wrapping up its work in the trench and driving 62 feet (18.8 meters) toward an area nicknamed Middleground, about halfway between Bonneville Crater and the rover’s landing point.

The boulder-strewn landscape becomes more treacherous the closer Spirit gets to the crater, which ejected boulders into the surrounding area when a meteor slammed into it eons ago, Manning said.

“We may see craters launched off from well below Gusev Crater that may have had some contact with ancient water,” Manning said.

This report includes information from Reuters and The Associated Press.